The present invention concerns an insect repellent (repellent) against flying, stinging, biting and sucking insects as well as pests of the genus acarina (mites and ticks).
Repellents are chemical substances which have a repulsive activity with respect to insects and arcarina. Practical importance has the use of these repellents in the field of human and veterinary hygiene in order to protect humans and animals from the activity of bloodsucking, stinging and biting pests, which are not only bothersome but also possess the potential to transmit diseases (malaria, FSME, lyme-borreliose and others). Repellents which are to be used and applied directly on the skin must be compatible with the skin, non-toxic, lighffast and sweat fast and they also must be acceptable from a cosmetic standpoint, i.e. not problematic to the skin (drying, generation of wrinkles) as well as unproblematic from the pharmacological standpoint (irritation, penetration into deeper layers of the skin and penetration into the blood cycle or the lymph cycle). Furthermore, the protection of the treated areas of the skin or the protection of humans and animals by using treated products should be maintained as long as possible and the activity of the repellent should be as broad as possible, i.e. the repellent should be active against a lot of different pests.
In the past and as well as, to a lesser extent, at present, ethereal oils such as citronella oil and lemongrass oil as well as clove oil, lavender oil, eucalyptus oil, as well as camphor are used as repellents. These products, however, show the following drawbacks:                they may contain problematic components, such as for example eugenol in clove oil, which has, in experiments shown mutagenic, carcinogenic and skin irritating activity, or cineol in the oil obtained from eucalyptus globulus, which immediately is able to give rise to tingling exanthemas,        they may only show a short term activity, since the ethereal oils evaporate from the skin due to the body temperature, so that reapplication becomes necessary in order to obtain the desired protection,        insufficient lightfastness may give rise to photosensitization as well as change of the product before application.        
In the recent past, the above-discussed repellents have been replaced by synthetic repellents. Synthetic repellents known in the prior art are for example phthalic acid dimethyl esters, 1,2-ethylhexane-1,3-diol, 3,4-dihydro-2,2-dimethyl-4-oxo-2H-pyrane-6-carboxylic acid-n-butylester, succinic acid dipropylester, N,N-diethyl-3-methyl-benzamide (DEET, also named N,N-diethyl-m-toluamide) and pyridine-2,5-dicarboxylic acid-di-n-propylester (Ullmanns Encyclopedia of Technical Chemistry, 4th edition, vol. 13, pages 237 and onwards, 1977). In the recent past, mainly hydroxyethyl-butyl-piperidine-carboxylate (1-piperidinecarboxylic acid-2-(2-hydroxyethyl)-1-methylpropylester) is used. However, these synthetic repellents often do not possess the required sweat fastness, irritate mucus membranes and are furthermore also able to penetrate through the uppermost layer of the skin, so that accumulation in the body may occur, in which connection must be noted that the resulting side effects have not yet been fully established although the general approach is that negative results are to expected.